Beneath her feet are two metal plates, and at her hand a digital display, a joystick and, somewhat alarmingly, a bright red emergency button.

As she pushes the joystick forward, the bionic legs take their first steps – a loud, industrial whirring strikes up and her right foot is raised, extended and placed forward. Her left slowly follows. As she looks up, a smile spreads across her face.

Exoskeletons, touted as devices that will allow the injured to walk, elderly people to remain independent for longer, the military to get more from soldiers and even turn all of us into mechanically enhanced humans, have captured the imagination of researchers across the world, from startups to Nasa.

For now, the most obvious – and tangible – application has involved allowing paralysed people to stand and walk. “It was a mixture of surrealism and just absolute, just the most exhilarating feeling,” says Morgan, describing her first experience of the technology four years ago.

Now 31, the artist, model and presenter of Channel 4’s 2016 Paralympic coverage was paralysed in a car accident aged 18 and has used a wheelchair ever since. The idea to try the exoskeleton, she says, came from the BBC security correspondent Frank Gardner, who uses a wheelchair after being shot while reporting from Saudi Arabia.

The exoskeleton, from Rex Bionics, offered a life-changing experience, according to Morgan. “It had been 10 years, give or take, since I had properly stood, so that was in itself quite overwhelming,” she says. The impact was far reaching. “It is not just about the joy of ‘Oh, I am standing’. It is the difference it makes, the way you feel afterwards, psychologically and physiologically – it is immeasurable.”

Returning to her wheelchair, says Morgan, is a disappointing experience. “I am walking in my dreams, so it does blur that line – that liminal space between real and dream, and reality and fantasy,” she says of the device.

The exoskeleton isn’t just about stirring excitement. As Morgan points out, there are myriad health problems associated with sitting for long periods of time. A report co-commissioned by Public Health England and published last year highlighted findings showing that, compared with those up and about the most, individuals who spend the longest time sitting are around twice as likely to develop type 2 diabetes and have a 13% higher risk of developing cancer.

Wheelchair users, adds Morgan, also face side-effects, from pressure sores to urinary tract infections. “It could be the difference between longevity and not for people like me,” she says of the exoskeleton.

The competition

About 40 of the Rex Bionic devices are currently in use worldwide, including in rehabilitation centres, says Richard Little, co-founder of the company. An engineer, Little says he was inspired to develop the system after his best friend and co-founder was diagnosed with multiple sclerosis.

But there is competition. As Little points out, the development of battery technology, processing power and components has brought a number of exoskeletons on to the market in recent years, including those from the US-based companies ReWalk and Ekso Bionics. “[They] offer a whole load of different things which are similar in some ways but different in others,” says Little. “[Ours] doesn’t use crutches,” he points out, adding that the innovation removes the risk of users inadvertently damaging their shoulders, and frees their arms.

There are tantalising signs that exoskeletons could do more than just aid rehabilitation or increase the mobility options for those who have experienced a stroke or spinal cord injury.

Sophie Morgan walks with the aid of Rex. Photograph: Teri Pengilley for the Guardian

While the bionic legs tried by Morgan are pre-programmed, researchers have developed exoskeletons controlled by a non-invasive system linked to the brain, allowing an even wider range of wheelchair users to walk. What’s more, when combined with virtual reality and tactile feedback, the systems even appear to promote a degree of recovery for people with paraplegia.

“All our patients got some degree of neurological recovery, which has never been documented in spinal cord injury,” says Miguel Nicolelis, co-director of Duke University’s centre for neuroengineering, who led the work.

It’s a development that excites Little, whose team have also been exploring the possibility of thought control with their own device.

Yet despite their transformative capabilities, the limitations of such bulky exoskeletons have left many frustrated. Tim Swift, co-founder of the US startup Roam Robotics and one of the original researchers behind the exoskeleton from Ekso Bionics, is one of them.

“It is a 50lb machine that costs $100,000 and has a half-mile-an-hour speed and can’t turn,” he says of his former work. “There are only so many applications where that makes sense. This is not a shift towards consumer, this is a hunt for somewhere we can actually use the technologies we are making.”

The dream, says Swift, is to create affordable devices that could turn us all into superhumans, augmenting our abilities by merging the biological with state of the art devices to unleash a new, improved, wave of soldiers, workers, agile pensioners and even everyday hikers. But in devising the underpinning technology, he says it is time to ditch the motors and metal approach that he himself pioneered.

While hefty, rigid devices can support someone with paraplegia, says Swift, such exoskeletons are too heavy and costly for wider applications – such as helping a runner go faster. The fundamental challenge, he adds, is to create a device that remains powerful while keeping the weight down. “I think you have two solutions,” he says. The first is to develop a new, lightweight system that efficiently uses battery energy to generate movement. The second, he says, is to stick with metals and motors but be more intelligent in how you use them.

Swift’s answer is based on the former – but it hasn’t received universal acclaim. “I have spent the last two and a half years literally getting laughed out of conferences when I tell people we are going to make inflated exoskeletons,” he says. “People think it is a running joke.”

But Swift is adamant that to produce a system that can be used in myriad ways to augment humans, be it on the building site, in the home or up a mountain, technologists must innovate. And air, he believes, is the way to do it. The result, so far, is a series of proof-of-concept devices, braces that look a little like padded shin-guards, that can be strapped on to arms or legs.

“The fundamentals allow you to have extremely lightweight structures [and] extremely low cost because everything is basically plastics and fabrics as opposed to precision machined metals,” he says. And there is another boon. “Because you can make something that is very lightweight without sacrificing power, you are actually increasing the power density, which creates these opportunities to do highly dynamic behaviours.”

In other words, according to Swift, exoskeletons made of inflated fabric could not only boost a human’s walking abilities, but also help them run, jump or even climb. “When I say I want someone to go into Footlocker and buy a shoe that makes them run 25% faster – [we are] actively looking at things that look like that,” he says.

Others agree with Swift about the need to reduce the clunkiness of exoskeletons, but take a different approach.

Augmenting humans

Hugh Herr is a rock climber, engineer and head of the biomechatronics research group at MIT. A double amputee, the result of a climbing accident on Mount Washington, Herr has pioneered the development of bionic limbs, inventing his own in the process. But it was in 2014 that his team became the first to make an all-important breakthrough: creating a powered, autonomous exoskeleton that could reduce the energy it took a human to walk.

“No one is going to want to wear an exoskeleton if it is a fancy exercise machine, if it makes you sweat more and work harder, what is the point?” says Herr. “My view is if an exoskeleton fails to reduce metabolism, one needs to start over and go back to the drawing board.”

To boost our bodies, says Herr, it is necessary to break the challenge down. “We are taking a first principle approach, and joint by joint understanding deeply what has to be done scientifically and technologically to augment a human,” he says.

For Herr the future is not inflatables (“pneumatics tend to be very inefficient,” he says) but minimalistic, stripping away the mass of conventional exoskeletons so that the device augments, rather than weighs down, the wearer. “If you separated the device from the human, it can’t even uphold its own weight,” he says.

The approach, he adds, was to focus on the area of the body with biggest influence when it came to walking, “Arguably the most important muscle to bipedal human gait is the calf muscle,” he says. “So we said in a minimalist design [with] minimal weight and mass, one arguably should build an artificial calf muscle.”

Boasting sensors for position, speed and force for feedback, and programmed to move and respond in a natural way, the device drives the foot forward, saving the wearer energy on each step. “Our artificial calf muscle pushes the human in just the right time in the gait cycle where the human is most inefficient and after that period gets out of the way completely,” he says.

Herr isn’t alone in focusing on such minimalist ankle-based devices. Among other pioneers is Conor Walsh at Harvard University who has created similar exoskeletons to help stroke patients walk. The devices are a million miles from the cumbersome bionic legs with with Morgan walked across the office, but then Herr believes the future for exoskeletons lies firmly with the augmented human.

“In the future when a person is paralysed, they won’t use an exoskeleton. The reason is we are going to understand how to repair tissues,” he says. “The only time to use an exoskeleton is if you want to go beyond what the muscles are capable of, beyond innate physicality.”

Making them look like second skins and behave like second skins is going to happen

In Bristol, Jonathan Rossiter is hoping to do just that with an even bolder approach: smart materials. “Fabrics and textiles and rubbers is a really good description of the things we are looking at,” he says. Professor of robotics at Bristol University and head of the Soft Robotics group at Bristol Robotics Laboratory, Rossiter believes exoskeletons of the future will look more like a pair of trousers. “Making them look like second skins and actually behave like second skins is going to happen,” he says.

The technology behind it, says Rossiter, will be hi-tech materials: rubbers that bend when electricity is applied, or fabrics that move in response to light, for example. “We build up from the materials to the mechanisms,” he says.

Conscious of an ageing population, Rossiter believes a pair of smart trousers will prove invaluable in keeping people independent for longer, from helping them out of chairs to allowing them to walk that bit further. But he too sees them becoming popular gadgets, helping hikers clamber up mountains.

There is, however, a hitch. Scaling up smart materials from the tiny dimensions explored in the lab to a full-blown set of slacks is no small feat. “You are taking something which is [a] nanomaterial. You have to fabricate it so that it layers up nicely, it doesn’t have any errors in it, it doesn’t have any fractures or anything else and see if you can transpose that into something you can wear,” says Rossiter. In short, it will be a few seasons yet before your wardrobe will be boasting some seriously smart legwear.

But as technology marches on, the dream gets closer to reality. Herr, for one, believes commercial devices are a hop, skip and a jump away – arriving within the next two decades.

“Imagine if you had leg exoskeletons where you could traverse across very, very irregular natural surfaces, natural terrains with a dramatically reduced metabolism and an increased speed while you are jumping over logs and hopping from rock to rock, going up and down mountains,” he says, conjuring up a scene of a bionic, human gazelle.

“When that device exists in the world, no one will ever use the mountain bike again.”